Texas Instruments OPA1644AIPWR

Overview

OPA1644AIPWR from Texas Instruments is a quad-channel, JFET-input audio operational amplifier optimized for high-fidelity signal conditioning in professional and consumer audio systems. It delivers 5.1 nV/√Hz input voltage noise, 0.00005% THD+N at 1 kHz, 20 V/μs slew rate, rail-to-rail output swing, and operates from ±2.25 V to ±18 V supplies - enabling low-distortion pre-amplification and line-driver stages in analog mixing consoles and A/V receivers.

For engineers reviewing the OPA1644AIPWR datasheet, OPA1644AIPWR pinout, OPA1644AIPWR application, or OPA1644AIPWR equivalent, this page provides verified specifications, package-confirmed pin functions, real-world audio use cases, and two validated alternative parts with documented functional and application-level differences.

Technical Context

The OPA1644AIPWR implements a fully differential JFET-input stage paired with a robust rail-to-rail CMOS output stage, delivering ultralow distortion across wide common-mode voltage ranges (–0.1 V to V_S – 3.5 V) and high open-loop gain (120–134 dB). Its internal phase-reversal protection eliminates output inversion during input overdrive - critical in noninverting microphone preamp topologies.

Each of its four independent amplifiers features matched thermal and electrical characteristics, with channel separation exceeding –126 dB at 1 kHz, enabling multi-channel audio routing without crosstalk-induced imaging artifacts. The device maintains unity-gain stability while driving capacitive loads up to 100 pF without oscillation.

Key Specifications

Pinout & Package

TSSOP-14 package (5.00 mm × 4.40 mm), thermally enhanced for sustained audio output power dissipation; pin-compatible with SOIC-14 variant but with reduced footprint and improved θ_JA (135°C/W vs. 97°C/W).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar audio operational amplifier applications.

Compared with OPA1644IDR, the OPA1644AIPWR offers superior thermal performance in compact layouts; compared with OPA1678IDR, it retains JFET input advantages for high-source-impedance audio paths while trading minor noise/THD improvements for proven EMI resilience and phase-reversal immunity.

Availability

OPA1644AIPWR is available at Aetrix Electronics and suitable for professional audio equipment, broadcast studio monitors, and high-end A/V receivers requiring stable component supply, long-term lifecycle assurance, and traceable sourcing.

Supply support for OPA1644AIPWR includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Texas Instruments is a global semiconductor leader specializing in analog and embedded processing technologies, with decades of expertise in high-performance audio signal chain components.

The OPA164x product line was engineered specifically for audiophile-grade analog signal conditioning - emphasizing ultralow distortion, JFET input integrity, and robustness in real-world EMI environments.

FAQ

What is the maximum capacitive load the OPA1644AIPWR can drive without instability?

The OPA1644AIPWR maintains stability driving up to 100 pF capacitive load with 2 kΩ series resistance, as confirmed by Figure 19 and Figure 20 in the SBOS484D datasheet. For direct capacitive loads (e.g., long cables), a 24 Ω series resistor is recommended. Exceeding these conditions risks peaking or oscillation, especially at gains ≤ +10. Always verify stability with actual PCB parasitics in final layout.

Does the OPA1644AIPWR support single-supply operation?

Yes, the OPA1644AIPWR supports single-supply operation from 4.5 V to 36 V, as specified in Section 6.3 of the datasheet. However, its true JFET input architecture and rail-to-rail output require careful attention to input common-mode range (V_CM = 0.1 V above V_– to 3.5 V below V₊) and proper mid-rail biasing for AC-coupled signals. For best THD+N, dual-supply ±15 V is recommended.

How does the OPA1644AIPWR's EMI rejection compare to standard op-amps in 2.4 GHz environments?

The OPA1644AIPWR achieves 86.8 dB EMIRR IN+ at 2.4 GHz - significantly higher than typical general-purpose op-amps (<60 dB). This is validated in Figure 30 and Table 1 of SBOS484D. In practice, this means the OPA1644AIPWR rejects Bluetooth/Wi-Fi interference in compact audio PCBs without requiring additional RF filtering, preserving DC accuracy and low-frequency signal integrity.

Can the OPA1644AIPWR replace the OPA2134 in an existing design?

Direct replacement is not recommended without validation. While both are JFET-input audio op-amps, the OPA1644AIPWR has higher slew rate (20 V/μs vs. 2.5 V/μs), lower noise (5.1 nV/√Hz vs. 8 nV/√Hz), and different pinout (TSSOP-14 vs. SOIC-8). The OPA1644AIPWR also requires separate V+ and V– pins per package, unlike the dual OPA2134. Electrical re-characterization and layout review are mandatory.

What is the guaranteed operating temperature range for the OPA1644AIPWR?

The OPA1644AIPWR is fully specified from –40°C to +85°C ambient temperature, as stated in Section 6.3 and Section 7.1 of the SBOS484D datasheet. Its absolute maximum junction temperature is 150°C, and thermal metrics (e.g., θ_JA = 135°C/W for TSSOP) allow derating calculations for continuous operation in enclosed enclosures or high-power-density audio stages.